Phacoemulsification handpiece, sleeve, and tip

ABSTRACT

A phacoemulsification instrument that significantly reduces infusion fluid leakage by providing a silicone sleeve with a built in reinforcing member. Also, the sleeve has only a single infusion hole in order to provide better infusion fluid flow without causing turbulence in the eye. In addition, the present invention provides either a valve or a variable aperture aspiration tube in order to regulate the aspiration rate. Also, the present invention includes a single aspiration hole at the tip in order to amplify flow coming to the tip. To assist in cataract removal, the tip may be provided with a variety of different barrier and baffle configuration. A handpiece includes a variable capacity reservoir in the infusion line to account for surges in the aspiration line. The needle includes steps, angles and barriers to focus ultrasonic energy to aid in emulsifying nuclear tissue and to aid in pushing emulsified material in the direction of aspiration flow. A compressible sleeve is rotatably coupled to the handpiece to permit the handpiece and needle to be manipulated to a limited extent in the axial direction and rotated freely about the longitudinal axis while the sleeve remains stationary with respect to the cornea.

This is a division of application Ser. No. 08/458,409, filed Jun. 2,1995, now pending.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for surgically removing acataractous lens from a human eye. More specifically, the presentinvention relates to an improved flexible phacoemulsification sleevewith a built in reinforcing member, a phacoemulsification sleeve with abarrier connected to the tip to direct infusion from a single ormultiple infusion hole while permitting minimal or no occlusion, a tipfor a phacoemulsification handpiece with different configuration ofbarriers and baffles to increase cutting and a side opening to amplifyfluid flow to the tip, a phacoemulsification handpiece with a valve toregulate the rate of evacuation, a phacoemulsification handpiece with avariable aperture aspiration line, a sleeve that includes a built-inreservoir, a stepped inside ultrasonic needle to direct ultrasonic wavesto enhance emulsification and aspiration, and a sleeve that iscompressible and rotatably connected to the handpiece in a fluid tightmanner.

2. Discussion of the Related Art

The human eye contains a lens which focuses on the retina, the sensorymembrane that lines the eye and receives the image formed by the lens.Through trauma, age, disease, mutation, or naturally occurringprocesses, the natural crystalline lens may become opaque or cloudy andthus cease to clearly transmit and focus light. This clouding of thelens is known as a cataract.

In the last few decades, techniques have been developed to surgicallyremove the cataract lens and replace it with an artificial orintraocular lens. This cataract lens extraction process may be performedby a number of medically recognized techniques. One of the more wellknown and widely used techniques is phacoemulsification.

The phacoemulsification procedure involves placing two concentric tubesthrough a corneal incision of approximately three millimeters. Thisincision is made in the region of the limbus where a colored portion ofthe eye meets a white portion of the eye. The incision can also be madein the cornea. The inner tube, known as a needle, is ultrasonicallyvibrated such that its vibrating tip member operates to emulsify thehard nuclear material of the cataract lens.

In this type of surgery, the vibrating inner tube also functions as anaspirator so that the emulsified cataract lens material may be aspiratedout of the eye. The outer tube, known as a sleeve, functions as anirrigator allowing for inflow of saline fluid into the eye. The salinefluid serves several purposes. First, the presence of the saline fluidprevents the cornea from collapsing as the lens material is emulsifiedand aspirated. Second, the saline aids in the aspiration of the cataractlens material out of the eye. The concentric tubes of a handpiece of thesystem are attached to an external power source, fluid source, andvacuum source, which provide for controlled ultrasonic vibration,irrigation, and suction.

The importance of infusing a fluid into the eye during cataract surgerycannot be understated. The fluid infusion serves to maintain the eye inan inflated, pressurized condition during cataract removal. However,there are several factors that increase the difficulty with which theeye structure can be maintained and supported in an inflated,pressurized condition during cataract surgery.

One of the prevalent causes of diminished inflation of the eye duringcataract surgery is leakage of fluid from the eye. This leakage normallyoccurs between the edges of the incision and the exterior surface of theinfusion sleeve. This leakage can have significant deleteriousconsequences to the success of the surgery being performed.

One of the adverse consequences of fluid leakage is that there is atendency for the eye to deflate during the operation. This deflationcauses certain tissues within the eye to collapse on each other or onthe surgical instrument that extends into the eye. The tissues mostlikely to be damaged from the consequences of such fluid loss are thecornea, the iris, and the lens capsule, which surround the cataract. Onemethod of counteracting this fluid leakage is to increase the amount offluid flow in order to maintain proper inflation of the eye. However,this approach is not a satisfactory solution to the problem of fluidleakage from the eye because the greater the infusion of fluid into theeye, the more the flow becomes rapid and even turbulent. This can causedamage to the cornea, especially to the fragile cells that line theinside of the cornea.

The fragile cells that line the inside of the cornea are known ascorneal endothelium and cannot be regenerated by the eye. Once thesecells are damaged or destroyed, they cannot be repaired or replaced byhuman regeneration. Also, damage to the corneal endothelium can causepermanent damage to the cornea, resulting in corneal clouding anddecreased vision, all of which may require a corneal transplant. Itshould be noted that the most common cause of corneal clouding andcorneal transplantation in the United States today are complicationsfrom eye surgery for cataract removal and intraocular lens insertion.

As a result, the phacoemulsification procedure would be significantlyimproved if corneal damage as a result of fluid flow leakage duringintraocular surgery could be reduced or eliminated.

Most infusion sleeves used for phacoemulsification or intraocularsurgery are made of silicone or silicone-type material. However, the useof silicone sleeves presents significant problems with respect to fluidleakage between the incision edge in the eye and the exterior surface ofthe silicone infusion sleeve. This is due to the fact that the incisionin the eye must be larger than the silicone infusion sleeve, since thesilicone infusion sleeve is made from a soft, compressible material andcannot be used safely when inserted through an incision in the eye wherethere is a minimal amount of clearance between the incision and theexterior of the silicone infusion sleeve.

When there is a minimal amount of clearance between the exterior of thesilicone infusion sleeve and the incision in the eye, the incision tendsto compress the non-rigid silicone sleeve against the vibrating tip,resulting in a relative rubbing movement between the silicone sleeve andthe vibrating tip. This rubbing movement generates undesirable heat asthe needle in the tip is vibrated at relatively high frequencies. Theheat thus generated is extremely undesirable and can result in thermalburns and shrinkage of ocular tissue surrounding the silicone infusionsleeve.

The burning and shrinkage of ocular tissue is a serious problem that hassight threatening implications. The rubbing of the infusion sleeveagainst the vibrating needle also constricts the path for fluid flowinto the eye, thus impeding efforts to keep the eye pressurized andinflated.

In an attempt to reduce the infusion fluid leakage and the deleteriouseffects that can be caused by the undesirable friction, some infusionsleeves have been constructed from rigid non-compressible materials.Generally, these materials have consisted of teflon or metallic-basedcompositions. These rigid non-compressible infusion sleeves have beensomewhat successful in solving the constriction problems in the fluidflow path between the distal end of the infusion sleeve and thevibrating tip. In addition, these sleeves have also reduced the heatgeneration and thermal burns associated with silicone-type sleeves.

While rigid, non-compressible sleeves are capable of being insertedthrough smaller incisions that reduce leakage through the clearancebetween the rigid, non-compressible sleeve and the incision, there isstill a significant amount of leakage. The primary cause of thisremaining leakage is that the cross section of the rigid,non-compressible sleeve does not match the shape or contour of the eyeincision. As a result, there are fairly substantial gaps between therigid, non-compressible sleeve exterior surface and the eye incision.This is due to the fact that the collagen fiber structure of the cornearesists deformation and does not readily assume the shape of theinfusion sleeve.

Other attempts to reduce the infusion fluid leakage and associated sideeffects, such as the one disclosed in U.S. Pat. No. 5,084,009 toMackool, include using a double sleeve system with the inner sleevebeing made from a rigid material such as teflon and the outer sleevebeing made from a flexible material such as silicone. However, there arestill many problems with this type of approach. For example, a doublesleeve system requires a stepped titanium needle. The needle 106 is notillustrated as being stepped in the '009 patent, however, only the mostdistal end of the needle is illustrated. In practice, this double sleevearrangement requires a stepped titanium needle. Additionally, thisarrangement requires more parts (i.e., teflon sleeve inside and asilicone outside sleeve). The teflon sleeve must be cut along its entireaxial length to be placed around the posterior part of the needle,because the needle contains a threaded posterior part and a steppedanterior part. Since both the thread and step are larger than thediameter of the sleeve, the only way to get the teflon sleeve on theneedle is to cut the sleeve along its entire length.

Additionally, with respect to the phacoemulsification sleeve, prior artdevices use two infusion ports in order to improve fluid flow. However,the use of two ports or holes tends to cause turbulence in the eye.Thus, there is a need for improved flow sleeves that reduce orcompletely eliminate turbulence in the eye and direct infusion away fromthe aspiration hole.

As to the handpiece used in phacoemulsification procedures, it should berecalled that the inner tube is used for aspiration, while the outertube is used for irrigation. During surgery, it is often desirous tochange the rate of aspiration. However, if the rate of evacuation oraspiration is too high, undesirable intra-ocular surges may occur. Thus,there exists a need for a phacoemulsification handpiece, where theaspiration can be reliably and accurately controlled.

Regarding the tip or needle that performs the actual cutting away of thenuclear material as it is ultrasonically vibrated, different designshave been proposed in order to increase cutting. However, these designssuffer from emitting ultrasonic energy in the eye and not emulsifyingefficiently.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide aphacoemulsification sleeve that significantly reduces infusion fluidleakage by providing a silicone sleeve with a built-in reinforcingmember. It is also an object of the present invention to provide aphacoemulsification sleeve with barriers or vanes or steps that directinfusion fluid flow away from the aspiration hole and minimizeturbulence in the eye.

It is yet a further object of the present invention to provide aphacoemulsification handpiece having a valve which will close when therate of evacuation is too high, in order to prevent intraocular surges.A still further object of the present invention is to provide aphacoemulsification handpiece with a variable capacity reservoir in theinfusion line to vary the amount of infusion flow to account for surgesin the aspiration line tubing. The surges in the aspiration line woulddecrease the intraocular pressure.

It is a further object of the present invention to provide aphacoemulsification needle with a single aspiration hole on one side toamplify the flow coming to the tip. It is a further object to provide aneedle with different configuration of barriers, baffles, steps in orderto increase cutting and suction effect within the needle.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious to thoseskilled in the art from the description itself, and further will beappreciated by those practicing the invention and using the resultingphacoemulsification device.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and still further objects, features and advantages of thepresent invention will become apparent upon consideration of thefollowing detailed description of a specific embodiment thereof,especially when taken in conjunction with the accompanying drawingswherein like reference numerals in the various figures are utilized todesignate like components, and wherein:

FIGS. 1A and 1B are cross-sectional and front views, respectively, ofthe of the silicone phacoemulsification sleeve with a built-inreinforcing member;

FIGS. 2A and 2B are cross-sectional and front views respectively of thesilicone sleeve inserted through an incision in the cornea;

FIGS. 3A-G are a top and side views of a phacoemulsification sleeve witha single infusion hole with internal or external steps to directinfusion;

FIG. 4 is a side view of a phacoemulsification handpiece or anirrigation-aspiration handpiece having a valve to constrict theaspiration line;

FIG. 5 is a schematical side view of a phacoemulsification handpiecewith a variable aperture aspiration line;

FIGS. 6A-F are side and front views showing various shaped needles;

FIGS. 7A-B are side views of a phacoemulsification needle with a hole onone side and a single infusion hole in the sleeve;

FIGS. 8A-D, 9A-D, 10A-D, 11A-D, 12A-D show different shapes of theemulsification end of the needle;

FIGS. 13A-B, 14A-B, 15A-B; 16A-B, 17A-B show different sizes and shapesof aspiration holes;

FIGS. 18A-B, 19A-B, 20A-B show concave, convex and angled surfaces whichare designed to direct ultrasonic waves;

FIGS. 21A-B, 22A-B, 23A-B, 24A-B, 25A-B, 26A-B and 27A-B show multipleaspiration holes;

FIG. 28 is a side view of handpiece assembly including a siliconemembrane which acts as a reservoir chamber for infusion fluid;

FIG. 29 is a side view of the handpiece assembly of FIG. 28 with thesilicone membrane being shown collapsed during an aspiration surge;

FIG. 30 is a side view of a phacoemulsification needle showing one ofthe different configurations of barriers and baffles;

FIG. 31 is a front view of a phacoemulsification needle employing one ofthe different configurations of barriers and baffles;

FIG. 32 is a front view of a phacoemulsification needle employing one ofthe different configurations of barriers and baffles;

FIGS. 33A-B, 34A-B, 35A-B, 36A-B, 37A-B and 38-42 show various shapebarriers which can be placed on the inside or outside of the needle

FIGS. 43 and 44 show a top and side view of a needle having a singleaspiration hole and specially designed internal and external surfaces toenhance the emulsification and the aspiration effect;

FIG. 45 shows a barrier similar to the embodiment illustrated in FIGS.33A-B but with the barriers set further back within the needle;

FIGS. 46 and 47 illustrate various barrier shapes and steps disposedwithin the needle to enhance the emulsification and aspiration;

FIG. 48 illustrates a stepped needle which enhances emulsification andthe aspiration effect;

FIGS. 49 and 50 are sectional views of additional embodiments of needletip;

FIG. 51 is a side view of a compressible sleeve according to the presentinvention; and

FIG. 52 is a anterior view of the compressible sleeve inserted into anincision in the cornea.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The phacoemulsification sleeve 10 of the present invention is a siliconesleeve with a built-in reinforcing member. The sleeve can be used in anultrasonic handpiece similar to the one disclosed in Applicant'scommonly owned U.S. Pat. No. 5,242,385 to Strukel, the disclosure ofwhich is hereby incorporated by reference. The sleeve is essentially asilicone sleeve of approximately 0.005 inches thickness with an overalldimension of approximately 1.0 inch, as shown in FIG. 1. In a preferredembodiment of the present invention, interwoven in the silicone walls ofthe sleeve are strands of teflon or metallic-based material 12 toprovide a rigid frame for the silicone walls. In an alternativeembodiment, the teflon or metallic material is in the form of a spiralor single strand that are embedded in the silicone walls of the sleeve.Alternatively, the sleeve could be impregnated with strands of fiberglass or kevlar which will also act as a reinforcing member. Of course,the sleeve could be reinforced with any number of different devices solong as the reinforcing member has a higher durometer (i.e., is harder)than the silicone.

The resulting sleeve has the advantages of both a rigid sleeve and acompressible sleeve, without suffering from the deleterious effects thatplague each individual approach. By having a relatively compressibleouter layer, the sleeve of the present invention is able to be deformedslightly in order to match the shape or contour of the eye incision 14,in the cornea 15, as illustrated in FIGS. 2A-2B. However, because thepresent sleeve has a built-in rigid frame, it is not deformable to theextent that a completely compressible silicone sleeve would be deformed.This reduction in deformation avoids the prior art disadvantages such asrubbing between the silicone sleeve and the vibrating tip that resultsin heat generation and thermal burns, as well as constriction of thefluid flow path into the eye.

During phacoemulsification the ultrasonic needle radiates ultrasonicenergy from its tip into the eye and pushes fluid and lens material awayfrom the tip. The flow through the aspiration port brings the materialto the tip. The ideal effect is to efficiently bring the cataract to thetip, completely emulsify the cataract and aspirate the emulsifiedcataract through the ultrasonic needle. To enhance the emulsification,surfaces can be added to the inside or outside of the ultrasonic needlewhich will direct ultrasonic waves in the desired direction.

Ultrasonic needles are currently manufactured of titanium and have agenerally circular cross-section as illustrated in FIGS. 6A and 6B. Theneedles 16 are used for phacoemulsification and for cutting and removingtissue during surgery. Other cross sectional shapes such as a triangle,as illustrated in FIGS. 6C and 6D, or polygonal shapes, such as ahexagon, as illustrated in FIGS. 6E and 6F can be used to improve thecutting and emulsification properties of the needle. In addition, theuse of non-circular cross-sectional needle shapes will provide a flatsurface which may be a more practical surface to work with to weld ormachine other surfaces to the needle. These additional surfaces wouldthen vibrate with the needle. The surfaces, which will generateultrasonic energy, can be arranged so that the ultrasonic energy isdirected in the preferred areas.

Conventionally, ultrasonic needles have been manufactured havingcircular openings at the distal end. This opening is known as theaspiration hole 18. The aspiration opening within the needle is simplymade by drilling a throughbore in the titanium shaft. An alternativemethod of forming the needle 16 would be to not drill the holecompletely through the needle but to leave the distal end of the needleclosed. In other words, a blind bore would be drilled into the needle.An aspiration hole 18 would then be provided on the side of the needle16. An advantage of providing the aspiration hole 18 in the side of theneedle is that the distal axial end of the needle can then be made, bymachining, to any desired shape, such as a flat surface or a slantedwedge shape, as illustrated in FIGS. 7A and 7B. Numerous other endconfigurations are illustrated in FIGS. 8A-27B. A further advantage ofplacing the aspiration hole 18 in the side of the needle 16 is that thehole 18 can be placed anywhere along the needle surface and can be sizedand/or shaped depending on the needs of the user. A further advantage isthat with the closed tip, additional ultrasonic energy will be emittedfrom the closed tip surface which will aid in emulsifying tissue. Thespecific shape of the tip, including the angle, concavity, convexity,etc. can be designed to selectively focus ultrasonic energy.Additionally, surface area can be designed to emit either a large orsmall amount of ultrasonic energy. Generally, the larger the surfacearea, the larger the amount of ultrasonic energy which will begenerated. In certain portions of the tip it is important to emit lessultrasonic energy to reduce the likelihood of breakage to the posteriorcapsule.

The ultrasonic waves radiate from the metallic surfaces. Accordingly,the surface of the tip could be modified so that it will intensely focusthe ultrasonic energy to emulsify tissue. However, if the surface isdesigned to focus low ultrasonic energy, that surface can be used toselectively clean tissue without the emulsification of tissue takingplace. Additionally, if the ultrasonic energy is finely focused, thatenergy can be used to cut the tissue. Accordingly, the surfaces of thetip can be designed to be tissue specific in its ability to focusultrasonic energy. Various embodiments of ultrasonic needles 16 areillustrated in FIGS. 7A-27B. Each of these needle embodiments have holeof various sizes and shapes and various needle surfaces to vary theamount of focusing of the ultrasonic energy and the amount of aspirationthrough the aspiration hole 18.

As discussed above, conventional ultrasonic needles have only oneaspiration port 18 which is disposed at the axial distal end of theneedle. Applicants have discovered that the addition of a secondaspiration port, disposed near the main aspiration port or even as partof the main aspiration port can provide numerous advantages in the useof the needle 16. FIGS. 24A and B illustrate an embodiment where thesecond aspiration port 18' can be disposed as being a part of the mainaspiration port 18. For example, during certain uses of the needle youwill want to build a vacuum in order to hold tissue at the tip. This isespecially true during certain types of cataract surgery, where it isdesirous to occlude the tip during either the "divide and conquer" orthe "phaco chop" techniques of cataract surgery. During thesetechniques, it is often desirable to hold the nucleus on the phaconeedletip. Obviously, it will be necessary to cover both aspiration holes tobuild a vacuum. However, during the emulsifying of tissue in the primaryport, it is often advantageous to have a secondary aspiration portavailable to assist in the further aspiration of the emulsified tissue.

Referring to FIGS. 3A-36 a sleeve 10 having an infusion port 17 isillustrated. Sleeve 10 is illustrated as having baffles 19 disposed oneither the interior or exterior surface adjacent to the infusion port 17to assist in directing the flow of infusion fluid. As illustrated inFIG. 3A, the baffle 19 can be disposed on the outer portion of thesleeve 10 in an area disposed between infusion port 17 and the distalend of the sleeve 10. In FIG. 3A the baffle directs an infusion fluidaway from the aspiration port. However, if desirable, the baffle 19 canbe placed on the opposite side of the infusion port 17, as illustratedin FIG. 3B to direct the infusion fluid in the forward direction towardsthe distal end of the sleeve 10.

As illustrated in FIG. 3E, the baffle 19 can be disposed within theinterior of the sleeve 10 between the infusion port 17 and the distalend of the sleeve. Alternatively, as illustrated in FIG. 3F, the baffle19 can be disposed on the proximal side of the infusion port 17.Additionally, as illustrated in FIG. 3G, a baffle 19 can be disposed onboth the exterior and interior surface of sleeve 10. As illustrated inFIG. 3G, the baffles are located on the distal side of infusion port 17.However, just as has been illustrated in FIGS. 3B, 3D and 3F, baffles 19could be disposed on proximal side of the infusion port 17.

Referring now to FIGS. 4 and 5, a phacoemulsification handpiece 11according to the present invention is shown. The handpiece 11 has avalve 20 in the aspiration line. The function of the valve is toconstrict the flexible tubing of the aspiration line to createresistance in the aspiration line. Also, the valve may be used to changethe flow characteristics at the needle tip. The valve may be controlledeither at the phacoemulsification machine control panel or directly atthe handpiece. It should be pointed out that the valve control can besimply an on/off valve or a valve that allows for analog-type controlwhereby the valve can be adjusted to any precise level betweencompletely on and completely off. In the preferred embodiment of thepresent invention, the valve is located at the anterior portion of thehandpiece.

The handpiece of FIG. 4 has a valve 20 which is preferably controlled sothat it can be adjusted to any precise level between completely on andcompletely off. The valve can be positioned at position C in FIG. 4which is within the handpiece, or at position B immediately behind thehandpiece or at position A, which is adjacent to the housing for theaspiration pump. The valve is controlled by a control console whichreceives signals from a pressure transducer (not shown) which detectsthe fluid pressure within the aspiration conduit. Upon the detection ofthe varying pressure within the aspiration line, the control consoleautomatically actuates the valve to variably increase or decrease thecross-sectional area of the aspiration conduit to ensure substantiallyconstant pressure within the conduit.

In the embodiment illustrated in FIG. 5, a valve 21 is disposed withinthe handpiece 11. This valve 21 is preferably of the type that is anon/off valve, as discussed above. Upon the detection of a pressuresurge, the control console immediately sends a signal to close valve 21.Simultaneously, valve 23 is opened to release relatively high pressurefluid from a sterile fluid container into the aspiration conduit.Thereafter, the bottom valve 21 is opened, the full effect of the surgeis erased and then valve 23 is closed once again. The system is thenready to detect and control the next surge within the aspiration line.

The advantages of an on/off valve, such as valve 21, include that when apiece of cataract occludes the phaco tip, vacuum will build up in theaspiration line. When that occluded piece is emulsified, there stillwill be a vacuum in the aspiration line and a surge will be created thusreducing the intraocular pressure. When a pressure transducer in theaspiration line detects a rapid change in vacuum, the valve in thehandpiece can be instantaneously closed and a release of sterile fluidin the aspiration line can occur to remove the vacuum and the handpiecevalve can then reopen. This valve, by closing instantaneously andopening immediately after fluid is released into the aspiration line,will prevent surges of intraocular pressure.

Referring now to FIGS. 28 and 29, a handpiece assembly 11 that includesa collapsible silicone membrane 22 is illustrated. The silicone membrane22 is disposed radially outside of the needle 16 and defines an annularreservoir chamber 24 disposed between the silicone membrane 22 andneedle 16. The reservoir is in fluid communication with the infusionfluid as it passes through the handpiece assembly and out through theinfusion sleeve port near the needle tip. The silicone membrane is madefrom a soft elastic material so that the membrane 22 can collapse duringan aspiration surge during use of the ultrasonic handpiece. Typically,when an aspiration surge occurs the relatively large amount of fluidwithin reservoir 24 is of a sufficient volume so that this fluid can beimmediately withdrawn from the reservoir and introduced into theintraocular area, which results in an immediate compensation for thefluid lost from the surge. As is well known, a drop in intraocularpressure can cause considerable problems such as collapse of theintraocular tissue onto the vibrating phaco needle. Accordingly, thereservoir 24 is designed to provide additional infusion fluid in theintraocular area as soon as an aspiration surge occurs. The reservior islocated immediately adjacent to the needle tip to mimimize the time ittakes to replace the intraocular fluid. The surge will cause a decreaseof intraocular pressure and will therefore provide a suction effect towithdraw the fluid contained within reservoir 24. This suction effectcauses the membrane 22 to collapse, as illustrated in FIG. 29. An airvent 26 is provided radially outside of the silicone membrane 22 topermit membrane 22 to collapse freely.

Referring now to FIGS. 30-42, a series of barriers are illustrated,which are attached to the walls of the ultrasonic needle 16. Thebarriers permit limited or no occlusion at the tip of the needle toenhance emulsification of tissue. As discussed above, occlusion of thetip can create a surge of fluid flow upon break up of the tissue causingthe occlusion. This surge in fluid flow can cause a collapse of theintraocular pressure within the eye which is a condition that should beavoided. In addition, the barriers also provide an additional ultrasoniccutting surface to enhance the cutting and emulsification ability of thetip. The barriers are structural members, such as bars, baffles, wedges,etc. which are attached to the walls of the needle 16.. A barrier 28 isillustrated in FIG. 30. Other embodiments of barriers including a singlebar 30 disposed in the center of the needle or double bars 32, 34disposed about the center of the needle are illustrated in FIGS. 31 and32, respectively. The bars 30, 32, 34 prevent nuclear tissue frompenetrating into the tip beyond a predetermined amount. Otherembodiments of barriers are illustrated in FIGS. 33A-42. For example, inFIGS. 33A. and B, an annular ramp shaped barrier 36 is disposed withinthe tip 16. A wedge shaped plate barrier 38 which does not extend fullyacross the inside of the tip is illustrated in FIGS. 34A and B. A pairof spaced apart bars 40, 42 are illustrated in FIGS. 36A and B. Abarrier 44, 46, illustrated in FIGS. 35A and B, is disposed on the outersurface of needle 16. These barriers 44, 46 do not assist in preventingan occlusion, but they do provide an additional surface from whichultrasonic energy can be generated. Other barrier embodiments areillustrated in cross-section in FIGS. 38 and 42. Clearly, almost anytype of geometric shape can be used to assist in permitting a limitedocclusion of the tip and to aid in emulsifying tissue.

Referring now to FIGS. 37A and B, barrier 42 is illustrated for use in amodified tip 16'. Tip 16' has a wedge shaped distal end surface 48 whichprovides a large metallic surface area for ultrasonically cuttingtissue. The ultrasonic energy from surface 48 is directed in an oppositedirection with respect to the aspiration port 18. A tip similar to theone illustrated in FIGS. 37A and B is illustrated in FIGS. 43 and 44.The angled surface 50 disposed inside of the needle 16' can be used tofocus energy towards the aspiration port 18, but within the needle 16',to aid in the emulsification of tissue. Other surfaces within thatneedle including surface 52 and a stepped shoulder surface 54 assist inthe suction of the nuclear tissue after it has been emulsified. Surface52 also is disposed within the line of ultrasonic energy that has beengenerated from surface 50 to effectively prevent this energy fromcausing damage to the surrounding tissue. Surface 52 is preferably aspherical surface, and can simply be formed by drilling a blind boreinto the shaft 16'. Surface 52 would be the distal portion of the blindbore. Exterior surface 53 is a blunt surface which emits ultrasonicenergy at a sufficient energy level to be able to split the cataract.However, the energy generated by surface 53 dissipates quickly so as tominimize the risk of damaging to the posterior capsule.

FIG. 45 illustrates a needle that includes a ramp shaped annular barrier56 whose ramp shaped surface 58 is directed towards the needle tip tofocus ultrasonic energy across the aspiration port 18. The stepped rearshoulder surface 60 of the ramp 56 is used to assist in the suction ofthe nuclear tissue after it has been emulsified. In most uses it isdesirous to contain the ultrasonic energy within the needle to minimizethe ultrasonic radiation which can cause damage to the intraoculartissue. In the embodiment illustrated in FIG. 45, ultrasonic energygenerated by ramp surface 58 is prevented from exiting the needle by theneedle's interior surface.

The present inventors have found the use of steps, angles, and barrierswithin the ultrasonic needle useful to focus ultrasonic energy acrossthe aspiration port to aid in emulsifying nuclear tissue and to aid inpushing emulsified material in the direction of the aspiration flow.

FIGS. 46-50 illustrate various embodiments of needle tips which achievethese results. FIG. 46 illustrates a tapered needle 16 that has aninternal annular shaped ramp 62 similar to ramp 56 illustrated in FIG.45. In addition, the front tapered end surface 64 of the needle 16 alsoradiates ultrasonic energy within the internal area of the tip to assistin the emulsification of nuclear tissue.

FIG. 47 illustrates an annular shaped ramp surface 66 that has aforwardly directed ramp surface 68, a reduced diameter passageway 70,and a stepped shoulder surface 72. Ramp surface 68 emits ultrasonicenergy to aid in the emulsification of tissue, whereas shoulder surface72 emits ultrasonic energy to assist in the suction of the emulsifiedtissue.

FIG. 48 illustrates a needle tip 16 that has the tip end 71 off-center(i.e., not concentric) with respect to the main portion of the tip 16.An internal ramp surface 74 emits ultrasonic energy adjacent to theaspiration port 18 to assist in the emulsification of nuclear tissue. Astepped shoulder surface 76 assists in the suction of that emulsifiedtissue by generating ultrasonic waves in the direction of flow.Additionally, an external ramped surface 73 emits ultrasonic energy toaid in the cutting and emulsifying of nuclear tissue.

FIG. 49 illustrates a needle tip 16 that has a wedged shape front tipsurface 78. Surface 78 emits ultrasonic energy outside and forward ofthe tip end to assist in the cutting of nuclear tissue. In addition, ashoulder surface 80 disposed adjacent to the aspiration port 18 assistsin pushing the material into the interior of the needle tip 16. Internalsurfaces 82, 83 also emit ultrasonic radiation energy to assist in theemulsification of nuclear tissue.

FIG. 50 illustrates an embodiment similar to that illustrated in FIG. 49in that a front wedged shape surface 84 and ramp surfaces 86, 87 areutilized in a similar manner to surfaces 78, 82 and 83 in the embodimentillustrated in FIG. 49.

Referring now to FIGS. 51 and 52. A compressible sleeve 88 isillustrated. Sleeve 88 includes an accordion section 90 to permit thesleeve 88, once it is connected to the handpiece 11 (not shown in FIGS.51 and 53) at area A, to move axially with respect to the handpiece.Sleeve 88 is connected to the handpiece by a fluid tight connection,which permits the handpiece 11 to rotate freely with respect to thesleeve 88. When the tip end of the needle 16 is inserted into theincision 14 of the cornea, the forward end 92 of the sleeve 88 extendsthrough the corneal surface 16, such that forward end 92 substantiallymatches to the incision 14 in the cornea. Due to the accordion designand to the rotational coupling, the handpiece and needle can bemanipulated to a limited extent in the axial direction and rotatedfreely about the longitudinal axis while the sleeve 88 will remainstationary with respect to the cornea . Thus, this forward portion 92 ofthe sleeve acts similar to a plug to completely seal the incision in thecornea. In addition, the infusion port at the distal end of the sleeve92 is located near the cornea and away from the aspiration hole 18 ofthe needle. Thus, there is considerably less turbulence within the eyewhich provides for better aspiration of emulsified tissue. In otherwords, if the infusion port is located too close to the aspiration port,the fluid will naturally follow a path of least resistance and shortcircuit directly from the infusion port to the aspiration port, whichclearly reduces the amount of tissue that can be removed from the eye orat the very least reduces the amount of time it takes to remove thedesired amount of tissue from the eye.

Having described the presently preferred exemplary embodiment of a newand improved phacoemulsification handpiece, sleeve, and tip, inaccordance with the present invention, it is believed that othermodifications, variations and changes will be suggested to those skilledin the art in view of the teachings set forth herein. It is, therefore,to be understood that all such variations, modifications, and changesare believed to fall within the scope of the present invention asdefined by the appended claims.

We claim:
 1. A surgical instrument for removing a cataract through anincision in an eye, comprising:irrigation means; aspiration means; ahandpiece shell; an infusion sleeve connected to said handpiece shelland connected to said irrigation means, said sleeve having a distal endand a proximal end; a needle disposed within said sleeve and connectedto said aspiration means; and an elastic membrane disposed radiallywithin at least one of said handpiece shell and at least a portion ofsaid sleeve and radially outside of said needle to define an annularvariable volume reservoir chamber disposed between said membrane andsaid needle to account for a surge of flow in said aspiration means. 2.The surgical instrument of claim 1, wherein said handpiece includes anair vent provided radially outside of said silicone membrane to permitsaid membrane to collapse freely.
 3. The surgical instrument of claim 1,wherein said membrane is disposed axially adjacent to said sleeve. 4.The surgical instrument of claim 1, wherein said membrane is made ofsilicone.